tbuckley/cabot-search huggingface dataset:
RTID-04. CLINICAL POTENTIAL OF TARGETING TRANSFORMING GROWTH FACTOR BETA 2 WITH OT-101 FOR POST-RADIATION CONSOLIDATION IN DIFFUSE INTRINSIC PONTINE GLIOMA
Authors: Fatih Uckun, Vuong Trieu
Journal: Neuro-Oncology (2022)

Abstract Diffuse intrinsic pontine glioma (DIPG) in children has a dismal prognosis with a median overall survival (OS) of 10 months and a 2-year overall survival rate of &amp;lt; 10% after standard radiation therapy. Chemotherapy does offer clinically meaningful benefits. Therefore, there is an urgent need for therapeutic innovations for treatment of pediatric DIPG. High-grade glioma cells, including pediatric glioblastoma and DIPG cells have been shown to produce transforming growth factor beta 2 (TGFB2) which has been implicated both as promoter of glioma cells and as a key contributor to the T-cell hyporesponsiveness of the tumor microenvironment (TME) towards glioma cells. OT-101 is a first-in-class RNA therapeutic designed to abrogate the immunosuppressive and tumor promoting actions of TGF-B2. At low micromolar concentrations, OT-101 reduces the TGFB2 secretion by human glioma cells, blocks their proliferation as well as migration, and restores the anti-glioma cytolytic function of patient-derived T-cells. In a Phase 2 clinical study, intracerebrally applied OT-101 administered via convection-enhanced delivery showed promising single agent activity in Recurrent/Refractory (R/R) high-grade glioma (HGG) (Uckun et al., Cancers. 2019 28;11(12):1892). The intrathecal administration of antineoplastic drugs directly in the CSF allows to bypass the selective filter of BBB, achieving significant concentrations of the antineoplastic agents in CSF, while reducing the likelihood of systemic toxicity. Informed by favorable safety pharmacology studies of intrathecally delivered OT-101 in rabbits and primates and encouraged by its single agent activity in adult patients with HGG, we decided to embark upon a multi-center, two-part, randomized Phase 1-2 study of OT-101 in pediatric patients with DIPG. Multiple doses of OT-101 will be administered after completion of radiation therapy as intrathecal bolus injections. The study is designed to determine: 1) the maximum tolerated dose (MTD) or recommended Phase 2 dose (RP2D) of OT-101, and 2) its efficacy in children with DIPG.
NIMG-29. ASSOCIATION OF PARTIAL T2-FLAIR MISMATCH SIGN AND ISOCITRATE DEHYDROGENASE MUTATION IN WHO GRADE 4 GLIOMA/GLIOBLASTOMA: RESULTS FROM THE RESPOND CONSORTIUM
Authors: Matthew Lee, Chiharu Sako, Sohil Patel, Suyash Mohan, Carmen Balana, Jill Barnholtz-Sloan, Andrew Sloan, Chaitra Badve, Laila Poisson, Brent Griffith, Thomas Booth, Joshua Palmer, Arnab Chakravarti, Spyridon Bakas, MacLean Nasrallah, Yoon Seong Choi, Adam Dicker, Adam Flanders, Wenyin Shi, Abhishek Mahajan, Rivka Colen, Daniel Marcus, Daniel Orringer, Christos Davatzikos, Rajan Jain
Journal: Neuro-Oncology (2022)

Abstract PURPOSE T2-FLAIR mismatch (T2FM) is a highly specific imaging biomarker for isocitrate dehydrogenase (IDH) mutation in low-grade gliomas. Previous T2FM studies are inconsistent for glioblastoma (GBM)/grade-4 glioma, partly due to low IDH-mutation prevalence in high-grade gliomas. We leveraged a large multi-institutional GBM/grade-4 glioma cohort to analyze the association of partial T2FM and IDH-mutation (T2-hyperintense, FLAIR-hypointense, nonenhancing, nonedema). METHODS We analyzed preoperative MRI of 1500 pathologically confirmed GBM/grade-4 gliomas with known IDH-mutation status from the ReSPOND consortium, consisting of the following institutions (sample size): Ivy GBM Atlas Project (33), Catalan Institute of Oncology (132), Case Western Reserve University/University Hospitals (132), New York University (55), Ohio State University (25), University of Pennsylvania (641), University Hospital Río Hortega (16), Yonsei University Health System (118), The Cancer Imaging Archive (93), Thomas Jefferson University (48), Tata Memorial Hospital (22), University of Pittsburgh Medical Center (156), and Washington University School of Medicine in St. Louis (57). Sequences were co-registered to a common anatomic atlas. Continuous variables were compared by t-test and categorical variables by Χ 2-test. RESULTS 71 (4.7%) were IDH-mutants, significantly younger (43±1 v. 62±12 years, p=5x10-37), and more likely to exhibit partial T2FM (20% v. 0.4%, p=1x10-43), frontal lobe predominance (68% v. 29%, p=7x10-12), nonenhancing components (T2/FLAIR-intermediate signal, nonedema; 45% v. 9%, p=1x10-22), and cystic components (smooth margins, no/minimal enhancement, homogeneous FLAIR suppression; 17% v. 3%, p=7x10-11) than IDH-wildtypes. 20 cases had partial T2FM (14 IDH-mutant, 6 IDH-wildtype). Sensitivity of partial T2FM for IDH-mutation was 19.7%, specificity 99.6%, positive predictive value 70%, and negative predictive value 96.1%. Subset analysis of 983 IDH-wildtypes with known MGMT methylation status (406 MGMT-hypermethylated) showed frontal lobe predominance was more common in MGMT-hypermethylated than MGMT-unmethylated (39.4% v. 24.3%, p=.02); other imaging characteristics did not significantly differ. CONCLUSIONS Partial T2FM is a highly specific imaging biomarker for IDH-mutation in GBM/grade-4 glioma.
TMET-18. TARGETING AMINO ACID METABOLIC VULNERABILITIES IN GLIOBLASTOMA
Authors: Shigeo Ohba, Takao Teranishi, Yuichi Hirose
Journal: Neuro-Oncology (2022)

Abstract Tumor cells have different metabolism from normal cell, which is called as cancer metabolism. In normal cells, asparagine is provided by asparagine synthetase (ASNS) from aspartate. On the other hand, in tumor cells, asparagine is needed to be taken in from outside the cells in addition to synthesized by ASNS within the cells, because of rapid growth of the tumor cells. Glioblastoma is one of the aggressive brain tumors, and temozolomide is frequently used. After glioblastoma cells acquire the resistance to temozolomide, no effective chemotherapy remained. The object of this study is to evaluate whether cancer metabolism, especially asparagine, could be a new target of treatment in primary and recurrent glioblastoma. Temozolomide-sensitive glioblastoma cell lines (U251, and U87), and U251- or U87 derived temozolomide-resistant cells, which were obtained after long treatment of temozolomide to parental cells, were used for the experiments. Genetical inhibition of ASNS using siRNA suppressed the proliferation of temozolomide-sensitive glioblastoma cells, inducing apoptosis. Adding of asparagine in the medium reversed the effect of siRNA targeting ASNS. L-asparaginase, which converts asparagine into aspartate, reduced the colonogenicity of glioblastoma cells. L-asparaginase increased the expression of mRNA of ASNS, and inhibition of ASNS potentiated L-asparaginase-induced anti-tumor effect. For temozolomide-resistant U251- or U87-derived cells, inhibition of ASNS also suppressed the colonogenicity of the cells, and inhibition of ASNS enhanced anti-tumor effect by L-asparaginase. In conclusion, targeting asparagine metabolism will be a therapeutic option for temozolomide-sensitive and temozolomide-resistant glioblastoma.
CSIG-09. THERAPEUTIC TARGETING OF PRENATAL PONTINE ID1 SIGNALING IN DIFFUSE MIDLINE GLIOMA
Authors: Dana Messinger, Micah Harris, Jessica Cummings, Chase Thomas, Tao Yang, Stefan Sweha, Rinette Woo, Robert Siddaway, Martin Burkert, Stefanie Stallard, Tingting Qin, Brendan Mullan, Ruby Siada, Ramya Ravindran, Michael Niculcea, Abigail Dowling, Joshua Bradin, Kevin Ginn, Melissa Gener, Kathleen Dorris, Nicholas Vitanza, Susanne Schmidt, Jasper Spitzer, Jiang Li, Mariella Filbin, Xuhong Cao, Maria Castro, Pedro Lowenstein, Rajen Mody, Arul Chinnaiyan, Pierre-Yves Desprez, Sean McAllister, Matthew Dun, Cynthia Hawkins, Sebastian Waszak, Sriram Venneti, Carl Koschmann, Viveka Yadav
Journal: Neuro-Oncology (2022)

Abstract Diffuse midline gliomas (DMG) are highly invasive brain tumors with rare survival beyond two years past diagnosis. The mechanism behind tumor invasion is currently not well understood. Previous reports demonstrate upregulation of the protein ID1 with H3K27M and ACVR1 mutations in DMG, but this has not been confirmed in human tumors or therapeutically targeted. Whole exome, RNA, and ChIP-sequencing were performed on the ID1 locus in DMG tissue. Scratch-assay migration and transwell invasion assays of cultured cells were performed following shRNA-mediated ID1-knockdown. In vitro and in vivo genetic and pharmacologic [cannabidiol (CBD)] inhibition of ID1 on DMG tumor growth was assessed. Additional in vitro experiments were performed to determine a potential mechanism of action for CBD-mediated effects. Self-reported CBD dosing information was collected from DMG patients. We found that increased ID1 expression in human DMG and in utero electroporation (IUE) murine tumors is associated with H3K27M mutation and brainstem location. ChIP-sequencing indicates a similar epigenetically active state at ID1 regulatory regions in human H3K27M-DMG tumors and prenatal pontine cells. Higher ID1-expressing astrocyte-like DMG cells share a transcriptional program with oligo/astrocyte-precursor cells (OAPCs) from the developing human brain and demonstrate upregulation of the migration regulatory protein SPARCL1. Genetic and pharmacologic (CBD) suppression of ID1 decreases tumor cell migration, tumor growth, and to a lesser extent invasion in both murine IUE and multiple patient-derived in vivo DMG models, improving mouse survival. ID1 knockdown significantly decreases the effect of CBD on migration, tumor growth, and invasion. CBD increases reactive oxygen species production, which also affects DMG cell proliferation in a non-ID1 mediated manner. Overall, we find that H3K27M-mediated reactivation of ID1 in DMG results in a SPARCL1+ migratory transcriptional program that is therapeutically targetable with CBD.
CTNI-10. RANDOMIZED PIVOTAL STUDY OF BLOOD-BRAIN BARRIER (BBB) DISRUPTION USING EXABLATE MODEL 4000 WITH STANDARD OF CARE (SOC) THERAPY IN NON-SMALL CELL LUNG CANCER (NSCLC) BRAIN METASTASES: LIMITLESS TRIAL
Authors: Manmeet Ahluwalia, Michael McDermott, Atulya Khosla, Arjun Sahgal, Mark Mishra, Achal S Achrol, Graeme Woodworth, Nir Lipsman
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND NSCLC is the most common cause of brain metastases. The Exablate focused ultrasound with circulating microbubble resonators uses the concept of real-time imaging to treat small target spots focusing energy through the skull in noninvasive manner, thereby disrupting the BBB. There is preclinical evidence of synergy of FUS-mediated BBB with immunotherapy beyond improved drug delivery due to BBB disruption (BBBD). METHODS LIMITLESS is a prospective, multi-center, randomized, two-arm, controlled, pivotal clinical trial to evaluate the safety and efficacy of additional targeted BBB disruption using Exablate Model 4000 for the treatment of NSCLC brain metastases in subjects who are undergoing planned pembrolizumab monotherapy compared to Pembrolizumab alone in 2:1 randomization. The inclusion criteria include age ≥ 18 years, KPS ≥ 70, NSCLC (EGFR and ALK negative) with up to 3 brain metastases, one of which meets the RANO-BM criteria for measurable Disease (1 cm x 1 cm) with normal organ function. The primary endpoint is to test superiority of Exablate BBBD targeted to their brain metastases over the standard of care without Exablate BBBD as determined by Objective Response Rate (ORR) based on RANO- BM by 6 months. The secondary endpoints include best objective response rate and time to response for brain metastases by treatment arm. Other end points include progression-free survival (PFS), overall survival (OS), Intracranial and extracranial PFS, quality of life assessments. The Bayesian design statistical analysis will assume superior ORR of 60% in Exablate group compared to 30% in SOC group for a total sample size of 96 subjects (64 subjects in Exablate and 32 in SOC) for 80% power using a two-sided Pearson's Chi-Square test with alpha = 0.05. For the upper-bound estimate ORR of 45% in Exablate group and 30% in SOC group will need 369 subjects (246 subjects in Exablate and 123 in SOC).
CSIG-29. EMPLOYING THE ZIKA VIRUS AS ONCOLYTIC VIROTHERAPY AGAINST PAEDIATRIC NERVOUS SYSTEM CANCER CELLS
Authors: Matthew Sherwood, Carolini Kaid, Thiago Mitsugi, Yilu Zhou, Yihua Wang, Paul Skipp, Juliet Gray, Oswaldo Okamoto, Rob Ewing
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND Malignant paediatric nervous system tumours, such as medulloblastoma, ATRT and high-risk neuroblastoma commonly harbour tumour cells with stem-like features which are highly tumorigenic and resistant to conventional therapies. These tumours can exhibit high lethality and may result in severe sequelae that significantly affect paediatric patients' quality of life. Oncolytic virotherapy exploits viruses that preferentially infect and destroy tumour cells. These viruses present a unique advantage in targeting highly heterogeneous cancers as they possess a secondary mechanism of action, through which they induce an anti-tumoral immune response. The Zika virus (ZIKV) is capable of infecting and destroying aggressive human paediatric brain tumour and neuroblastoma cells in vitro. ZIKV effectively reduces brain tumour size in mice (xenograft model) and canines (naturally occurring) and can induce an immune response against canine brain tumours. METHODS Employing global expression omics profiling of ZIKV infection and mapping of viral protein-host protein interactions, we aim to elucidate the mechanisms which underpin ZIKVs therapeutic properties, both at the molecular and cellular pathway levels. RESULTS Through extensive transcriptome profiling of ZIKV-infected paediatric brain tumour, neuroblastoma and NPCs, we have identified a variety of pathways which are involved in the ZIKV oncolytic response in the tumour cells and its neuro-dysregulation of NPCs. Despite both brain tumour and neuroblastoma cells undergoing ZIKV-induced oncolysis, we observed there to be a heterogeneous response within these different tumour cells at the molecular level to lead to oncolysis. Additionally, the infected tumour cells demonstrate elevated immune system profiles which alludes to the immune response that ZIKV may raise within the patient’s body against the paediatric tumour. Analysing our findings alongside the neuro-dysregulation we observe in our ZIKV-infected NPCs is allowing us to build a safety profile for employing a ZIKV-based therapy, whilst contributing to the growing knowledge of Congenital ZIKV Syndrome.
ANGI-06. CRISPRI SCREEN USING 3D BIOMIMETICS TO IDENTIFY NOVEL MARKERS OF GLIOBLASTOMA INVASION
Authors: Saket Jain, Erin Akins, Joseph Garcia, Sanjay Kumar, Manish Aghi
Journal: Neuro-Oncology (2022)

Abstract Despite the aggressive treatment regimen, patients with GBM have a very poor prognosis, with a median survival of less than 2 years. The main reason behind this poor survival is the infiltration of tumor cells into the surrounding normal tissue. These infiltrative cells escape both surgical resection and radiation therapy, leading to inevitable tumor recurrence. Current approaches have failed to recognize that infiltrating GBM cells extending beyond the tumor edge have evolved a unique adaptive cellular machinery due to local stressors in their microenvironment. Unfortunately, these cells at the invasive tumor front are often not the ones sampled in studies analyzing banked tumor tissue, Second, most studies of invasion have used two-dimensional (2D) culture systems coated with a thin layer of extracellular matrix proteins, which fail to capture the dimensionality, mechanics, and heterogeneity of GBM invasion. We addressed these limitations by using an advanced CRISPRi druggable genome screen to identify novel druggable markers of GBM invasion in a 3D engineered biomimetic model comprised of Hyaluronic Acid (HA) based matrix. To better understand druggable pathways underlying GBM invasion, we performed a large-scale CRISPRi screen with a sgRNA library that targets the druggable human genome (2,550 genes). In the primary screen, sgRNAs targeting 12 genes were enriched in the non-invasive fraction. Out of these 12 genes, 8 genes are associated with cellular metabolism or chromosome assembly. We then validated these 8 genes using small molecule inhibitors in our 3D-gel sphere cultures, from which we identified four druggable targets, SOD-1 and NDUFV2 associated with mitochondrial metabolism and AURKB and ACP1 related to centromere assembly and chromosome segregation. In follow-up to these novel findings linking mitochondrial metabolism and centromere assembly to GBM invasion, our next steps are to identify the mechanism linking these genes to GBM cell invasion followed by validation in vivo.
EPCO-06. THE IMPACT OF MISMATCH REPAIR DEFICIENCY (MMRD) ON SURVIVAL OF TEMOZOLOMIDE (TMZ)-TREATED PATIENTS WITH MGMT METHYLATED (M-MGMT) GLIOBLASTOMA (GBM): A CELLWORKS COMPUTATIONAL BIOSIMULATION PILOT STUDY
Authors: Michael Castro, Fabio Iwamoto, Manmeet Ahluwalia, Shahabuddin Usmani, Ansu Kumar, Shweta Kapoor, Rakhi Purushothaman Suseela, Shruthi Kulkarni, Jharana Mohanty, Vijayashree Shyamasundar, Adity Ghosh, Nagendra Prasad, Mamatha Patil, Sayantani Roy Choudhury, Jyoti Chauhan, Mohammed Sauban, Vishwas Joseph, Pallavi Kumari, Upasana Mitra, Anusha Pampana, Humera Azam, Poornachandra G, Annapoorna Prakash, Sayani Basu
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND TMZ-induced G:T mismatches trigger MMR to perform futile repair of O6-methylguanine leading to apoptosis. Without MMR, the G:T mutation is genomically incorporated to produce DNA mutation signature #11. Hypermutation ensues and may compromise survival without the redemptive benefit of immunotherapy. MMR genes are infrequently mutated or deleted. More commonly, MMRD results from epigenetic silencing, transcription failure, or micro-RNA compromising translation. METHODS Comprehensive genomic profiling and Cellworks biosimulation was utilized to diagnose MMRD and correlated with survival in 38 TCGA patients with newly diagnosed, IDH wildtype, m-MGMT GBM treated with adjuvant TMZ. The signaling pathway consequences for MutSα and MutLα were assessed. Kaplan-Meier curves were constructed for PFS and OS. RESULTS Patients were characterized: MMR proficient (Grp 1) and deficient (Grp 2). Half (19/38) had compromise of 1-10 pathways impacting MMR: 3 had deletions of MLH1 or PMS2. Others included deletions of EP300, CREBBP, KMT2A-D, ARID1A, HUS, or EXO1 and amplifications of KDM4A/C or MIR21/155. Grp 1 had significantly higher MMR biosimulation scores than Grp 2. (p=0.00082). The median PFS was 10.51 and 3.58 months (p=0.0072) and median OS was 16.96 and 9.40 (p=0.0059) months in Group 1&amp;2, respectively. CONCLUSIONS Up to half of GBM patients have MMRD caused by pathway dysregulation. Biosimulation of MMRD predicts early progression on TMZ, echoing the long-held observation that TMZ does not trigger apoptosis in MMRD cancers. The study also reports inferior OS for MMRD compared to the historical experience of unmethylated-MGMT patients, suggesting that TMZ-induced hypermutation may compromise survival. As lomustine does not rely on intact MMR, 2nd-line lomustine may have blunted the impact of MMR on OS. Alternatively, upfront lomustine might have produced superior disease control in MMRD patients. Computational biosimulation offers the opportunity to diagnose patients who should not receive TMZ despite m-MGMT and who could benefit from alternative adjuvant strategies.
CNSC-30. IN VIVO DYNAMICS OF ASTROCYTE-GLIOBLASTOMA TUMOR NETWORKS
Authors: Yvonne Yang, Ekin Reyhan, Marc Schubert, Robert Denninger, Niklas Wißmann, Rangel Pramatarov, Wolfgang Wick, Thomas Kuner, Frank Winkler, Varun Venkataramani
Journal: Neuro-Oncology (2022)

Abstract As one of the most aggressive incurable primary brain tumors, glioblastomas show a high invasivity and therapeutic resistance caused by their cellular and molecular heterogeneity. In previous studies, we showed that glioma cells interconnect using membrane protrusions called tumor microtubes to form a therapy-resistant malignant network. Here, we extend the concept of tumor networks to heterogeneous connectivity with the glial microenvironment. Using high-resolution light microscopy, ultrastructural tissue imaging, patch-clamp electrophysiology, intravital structural and functional microscopy, we characterize tumor-astrocyte connectivity. First, we used high-resolution light microscopy with immunohistochemistry and ultrastructural imaging to discover and characterize gap junctional connections between tumor cells and astrocytes. Next, we probed functional, heterotypic connections using dye filling with patch-clamp electrophysiology. Employing calcium imaging, we could demonstrate bidirectional communication patterns between tumor cells and astrocytes. We further characterized the stability of these astrocyte-glioma networks by using longitudinal imaging of single cells over several weeks in patient-derived xenograft models. For this, we used sulforhodamine 101 (SR101) as a marker for astrocyte-glioma connectivity to simultaneously visualize tumor cells and their glial microenvironment. The percentage of SR101 uptake in glioma cells increases over time, showing an increasing integration of tumor cells into the tumor-and astrocyte network during tumor evolution. Tumor cells, which are unconnected to other tumor cells or astrocytes, are the main drivers of invasion while a subgroup of glioma cells with stable astrocyte connectivity stay in place over several weeks. Lastly, we showed how these functional, heterotypic connections contribute to therapeutic resistance in the context of radiotherapy. In conclusion, we investigated multicellular networks between glioblastoma cells and astrocytes, their plasticity and role for therapeutic resistance.
TMET-25. MEK/ERK AND AMPK SIGNALING DICTATE VULNERABILITY TO FATTY ACID DESATURATION INHIBITION IN GLIOBLASTOMA
Authors: Alessandro Sammarco, Katharina Eyme, Roshani Jha, Hayk Mnatsakanyan, Rudolph Neustadt, Charlotte Moses, Ahmad Alnasser, Daniel Tardiff, Baolong Su, Kevin Williams, Steven J Bensinger, Chee Yeun Chung, Christian E Badr
Journal: Neuro-Oncology (2022)

Abstract Lipid metabolism is altered in many cancers. Glioma stem cells (GSCs), a subpopulation that contributes to molecular heterogeneity and therapeutic resistance of glioblastoma (GBM), are highly dependent on de novo lipid synthesis (DNLS) for energy production and proliferation. Although DNLS is a promising therapeutic target in GBM and other tumors, the molecular mechanisms that determine the dependence on DNLS remain largely unknown. In this study, we aimed to define the genetic drivers of vulnerability to DNLS inhibitors in GSCs and to explore the molecular mechanisms dictating resistance to a brain-penetrant inhibitor of stearoyl-CoA desaturase (SCD), a key enzyme involved in DNLS. Using an astrocyte model of gliomagenesis, we discovered that activation of RAS/MEK/ERK promotes vulnerability to DNLS inhibitors, whereas defective MEK/ERK activity drives resistance to SCD inhibition. Also, we identified the energy sensor AMPK as a downstream target of MEK/ERK and discovered an adaptive metabolic reprograming of GSCs dictated by AMPK activation. Shotgun lipidomics revealed that constitutive AMPK activation protects from SCD inhibition-induced lipotoxicity and endoplasmic reticulum stress and preserves the ability of transformed cells to form brain tumors in mice. Mechanistically, we found that AMPKs ability to circumvent lipotoxicity was achieved by altering the lipid composition and saturation state of cell membranes, and channeling potentially lipotoxic fatty acids into lipid droplets (i.e., lipid storage). These results strongly suggest that the efficacy of DNLS-targeted therapy can be dictated by the MEK/ERK and AMPK signaling status of GSCs. These data also suggest that MEK/ERK and AMPK signaling could be used as predictive biomarkers to understand which GBM patients are likely to respond to DNLS-targeted therapy. In conclusion, our data uncover an unexpected mechanism by which GSCs avoid a metabolic vulnerability and provides a rationale for integrating DNLS-targeted therapies for GBM treatment.